Contractor shall select 100 asthmatics. Select 100 controls for tissue typing matched by sex, race, and age. Obtain 10 families to participate in an HL-A family study of asthma. Select 100 patients from its sarcoidosis clinic. Select for tissue typing controls for the sarcoidosis study. Select 100 patients with extrinsic allergic alveolitis and select controls. Collect and process the clinical data.